The files tab should be the box that pops open when you add the torrent. You can uncheck them there. Also, you could set them not to start automatically and then change them to do not download once they are loaded into deluge.

However, I can't see what you say. Whenever I open a torrent file in Deluge, the window that pops-up is the one below and it's empty:

As you can see, there are no files there (I'm sorry, it's in Portuguese and I didn't manage to change the language, but the content is the same).I manage to visualize the files that are in a torrent file only after having it already downloading, then I look at the bottom and am able to see it like this: